What is Depth of Field? Examples for Better Understanding

Understanding Depth of Field

When learning photography, one of the foundational concepts to understand is depth of field. The definition of depth of field in photography also applies to videography, though it's used slightly differently.

In photography, it's captured in a single frame, while in videography, it can shift during a shot to guide focus, emphasize movement, and enhance the narrative flow.

Key Elements That Affect Depth of Field

Both the depth of field in photography and videography are influenced by several technical settings that determine how much of your image or video stays in focus.

Aperture:

Aperture is the opening inside a lens that controls how much light enters the camera. A wide aperture (low f-number like f/1.8) creates a shallow depth of field with more background blur. A narrow aperture (high f-number like f/11) increases depth of field, keeping more of the scene sharp.

Camera-Subject Distance:

The closer the camera is to the subject, the shallower the depth of field. This means the background will appear more blurred. Increasing the distance between them brings more of the scene into focus.

Focal Length of the Lens:

Focal length refers to the distance between the lens and the camera sensor when the subject is in focus. Longer focal lengths (e.g., 85mm or more) naturally produce a shallower depth of field, while shorter focal lengths (e.g., 18mm) tend to keep more of the scene sharp.

Sensor Size:

Larger camera sensors tend to produce a shallower depth of field compared to smaller sensors, even when using the same settings. This is why full-frame cameras often create a more pronounced background blur than smartphone cameras, which have much smaller sensors.

Application Section - When/Where to Use

How Depth of Field Is Used in Video Production:

In video production, depth of field is used as a storytelling tool. It can help guide attention, shape mood, and strengthen visual narrative.

Common Applications:

Directing Focus:

A shallow depth of field helps direct the viewer's attention to the most important subject in the frame. For example, in a close-up interview shot, the speaker is in sharp focus while the background is softly blurred. This makes the subject stand out and minimizes distractions.

Setting the Scene:

A deep depth of field is often used in wide landscapes or establishing shots, where it's important to show the environment clearly. In travel vlogs or documentaries, showing everything from the foreground to the background in focus helps viewers feel grounded in the location and take in more visual information.

Controlling Visual Clutter:

In busy environments, a shallow depth of field can simplify the frame by blurring out unimportant elements. When filming in a bustling city street or crowded room, isolating the subject with blur helps eliminate distractions and keeps the composition clean and focused.

Types and Examples in Popular Media

Depth of field comes in different styles, and each one can completely change the way a scene looks and feels. Below are the most common types of depth of field, along with how they're used in popular films.

Deep Focus: Django Unchained (2012)

Deep focus keeps everything in the frame, foreground, middle ground, and background, sharp and clear. This is often used in dramatic wide shots to give viewers the freedom to explore the scene visually.

Shallow Focus: The Master (2012)

Shallow focus creates a strong blur in the background, keeping only the subject in sharp detail. It draws attention directly to a character or object.

Rack Focus: Django Unchained (2012)

Rack focus refers to shifting focus from one subject to another within the same shot. It's often used to reveal new information or shift emotional emphasis.

Soft Focus: A.I. Artificial Intelligence (2001)

Soft focus gently blurs the image to create a dreamy, romantic, or nostalgic look. Unlike shallow focus, it doesn't sharply isolate the subject. Instead, it smooths the entire frame just enough to give it a warm, ethereal quality.

Split Diopter: Cape Fear (1991)

Split diopter shots use a special lens to keep two subjects, one close, one far, in focus at the same time, often creating a noticeable blur line in between.

Tilt Shift: A Serious Man (2009)

Tilt-shift lenses distort perspective to create a miniature or toy-like appearance, often paired with a shallow depth of field.

How to Measure Depth of Field

For beginners, achieving your desired depth of field can be tricky. Fortunately, there are several ways to measure or preview it, depending on your camera type and setup:

Can You Achieve Same Depth of Field of Different Sensor Size?

You can achieve the same depth of field across cameras with different sensor sizes, but only if you adjust your aperture based on the crop factor.

A crop factor is the ratio of a camera's sensor size compared to a full-frame sensor (which is considered the standard). Here's a quick look at some common sensor types and their crop factors:

To match the depth of field, divide the full-frame aperture setting by the crop factor. If you're shooting at f/18 on a full-frame camera, you'd use around f/12 on an APS-C and f/9 on a Micro Four Thirds to get a similar depth of field and field of view.

Practical Demonstration Section - How to Use

Now that you understand the definition of depth of field, it's worth noting that this effect isn't limited to what you capture on camera. You can also create or adjust it during the editing process. If your original footage doesn't have much background blur or you want to guide your viewer's focus better, you can use editing tools to fake or enhance the depth of field effect.

One of the tools that lets you do this easily is Wondershare Filmora. With built-in blur effects and smart cutout tools, you can highlight your subject, soften distracting backgrounds, or even mimic cinematic focus styles.

How to Edit the Depth of Field of a Video in Filmora

Step 1

Open Filmora and Import Your Clip: Open Filmora, start a new project, and drag your video into the timeline. Duplicate the clip—one will serve as the background, and the other will be used to isolate the subject.

Step 2

Apply a Blur Effect: Click on the bottom video layer (the background). Go to the Effects tab and search for blur effects like Depth Blur, Gaussian Blur, or Tilt-Shift. Drag the effect onto the clip and adjust the blur strength or depth.

Step 3

Isolate Your Subject: Select the top video layer. Then, head to Video > AI Tools to enable AI Portrait Cutout. This automatically removes the background from your subject, letting it stay sharp while the background stays blurred.

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